This invention relates generally to a welder's shield for electric arc welding, and more particularly concerns a welder's hood provided with means to reduce or prevent indirect radiation from being passed to the eyes of the wearer.
It is well known, even among welders, that the light from a welding arc is injurious to the eyes. Such a welding arc gives off ultra-violet and other harmful radiation which radiation may for example burn the retinas of the wearer's eyes. Consequently, the standard welding shield or helmet has a window of very dark glass to greatly reduce the radiation passing to the wearer's eyes from the arc. The welding shield may be of a type worn by the welder, e.g. being pivotally suspended from a headband, or may be of a type having a handle to be held with one hand of the welder in front of his face.
What is not so commonly known in the trade is the fact that indirect radiation from the arc may be passed to a welder's eyes, other than through the dark glass of the viewing means of the helmet, and that this indirect radiation may be very harmful to the welder's eyes. For instance, light from the arc may bounce off the welder's chest or a stainless steel tank or wall behind the welder, pass through the space between the welder's head and the inside surface of the face mask, and then be reflected off the inside surface of the mask or of the viewing window of the mask into the wearer's eyes; alternatively the arc from another welder may be reflected directly off of this window into the eyes of the first welder. After years of being subjected to such indirect radiation, the welder may not be able to weld for as long a period of time before he must stop to rest his eyes, and he may find the strength of his eyes has seriously deteriorated. Alternatively, often times this indirect radiation may have the same effect on the eyes of the welder as direct light from an arc, for example in conditions where this indirect light is of high intensity, e.g. welding in stainless steel tanks or with welders directly behind.
There are numerous helmets or shields described in the prior art, although few of these devices appear to provide a solution to the problem of this indirect radiation. For example, Canadian Pat. No. 392,792 of Schneider, issued Nov. 26, 1940 describes and illustrates a means associated with a welder's protective head mask for supplying fresh air to the wearer. The means comprises a cup, spring-mounted on the inside surface of the mask, urged towards the nose of the wearer and into flush engagement with the surface of the wearer's face about his nose. Fresh air is supplied to the wearer through hose means entering the cup.
Miscellaneous welders' shields, of general background interest, but which fail to provide a solution to the problem of harmful indirect radiation, include U.S. Pat. No. 2,578,171 of Bub, issued Dec. 11, 1951; U.S. Pat. No. 2,613,353 of Schnitzler, issued Oct. 14, 1952; Canadian Pat. No. 716,193 of Farr, issued Aug. 17, 1965; Canadian Pat. No. 911,652 of Raschke, issued Oct. 10, 1972; Canadian Pat. No. 938,001 of Finger, issued Dec. 4, 1973; and Canadian Pat. No. 989,216 of Feuk, et. al., issued May 18, 1976.
It is an object of the present invention to provide a welder's shield which will effectively protect the eyes of the wearer against indirect radiation which may be reflected to his eyes off the inside surface of the viewing window of the face mask or the inside surface of the mask. It is a further object of the present invention to provide such a helmet which will be both comfortable and operate effectively and conveniently if the wearer wishes to raise the mask to a position above the face or lower it into face shielding position.